As microelectronic devices continue to miniaturize, the thermal conductivity of both electronic packaging and semiconductor chips is becoming critical as the ability to dissipate the heat generated limits performance and reliability. Most polymers are thermal insulators, but can be used as thermal conductors once an appropriate filler is added. Typically, high filler loading levels are required to show significant improvements in conductivity, especially for spherical particles. In general, percolation threshold is defined as the concentration at which the particles become connected, forming a network, to attain the maximum conductivity. This concentration is dependent on filler size, shape, the alignment strategy, supramolecular interactions and interfaces. Unfortunately, these high loading levels, typically in the range of 50 to 66 wt %, adversely affect dielectric constant and mechanical properties of the host material. To this end, strategies designed to reduce the percolation threshold would provide a game-changing strategy that would benefit many technologies.
Broadly applicable methods and materials of reducing percolation threshold within polymer materials are needed.